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validate_ring3_state

strat9_kernel::arch::x86_64::ring3_diag

Function validate_ring3_state 

Source 
pub fn validate_ring3_state(target_rip: u64, target_rsp: u64, cs: u16, ss: u16)
Expand description

Validates all CPU preconditions for a safe Ring 3 transition via iretq.

§When to call

Immediately before the iretq trampoline. If this function returns, all prerequisites are satisfied. If a check fails it panic!s with a detailed diagnosis (bad GDT/paging/TSS, raw descriptor values, addresses involved).

§Arguments

  • target_rip – Ring 3 instruction pointer (ELF entry point)
  • target_rsp – User-stack top (must be 16‑byte aligned)
  • cs – Code-segment selector in the IRETQ frame (e.g. 0x2B)
  • ss – Stack-segment selector in the IRETQ frame (e.g. 0x23)

§Panics

Panics with an explicit message if any of the following is false:

  • CS/SS present in GDT with DPL=3, P=1; CS has L=1
  • target_rip and target_rsp are USER_ACCESSIBLE at every page level
  • target_rsp is 16‑byte aligned
  • TSS is loaded and rsp0 resides in kernel space